Wild world: Is the threat of a natural disaster growing in Britain?

Giant natural disasters may seem a distant threat to Britain but that doesn’t mean we should let our guard down.

Wipe out: Britain is not immune to natural disasters (Pic: Getty)

Rescuers in the Indonesian islands of Mentawai have called off the search for bodies following last month’s earthquake and tsunami, which killed 461 people. Disasters like this, and the Haiti quake in January that claimed 260,000 lives, are all too common to us – but only through the news.

While we like to moan about the weather in Britain, the reality is most people believe we are at little threat from natural disasters. However, behind the scenes, teams of scientists are constantly assessing the risks and threats from tsunamis, earthquakes, flooding and landslides, with some surprising results.

Tsunamis have hit Britain in the past, the most recent large wave resulting from the earthquake of 1755, near the Azores-Gibraltar fault zone, which devastated Lisbon, Portugal. Four hours later people in south-west Britain reported seeing two-metre waves crashing against the shore, displacing huge boulders.

A much larger tsunami hit the northern shores of Britain 8,000 years ago after an underwater landslide off the coast of Norway. The Storegga Slide resulted in 20m waves hitting Scotland and damage to the Shetland Isles can still be seen.

The most likely cause of an earthquake-created tsunami hitting Britain is from the same fault systems off Portuguese shores that created the 1755 event, says David Kerridge, head of earth hazards and systems at the British Geological Survey. ‘Taking the 1755 event as a reasonable worst case, we wouldn’t expect to ever see larger waves from that source,’ he says, before adding: ‘One or two metres might not sound like much but if you are standing on the beach it is big enough to be a danger.’

Another threat is a repeat of an underwater landslide, such as Storegga. A landslide of this magnitude is likely only every 100,000 years, says marine geologist Dave Long, but there are slope failures all along northern Europe.

‘With climate change, we are likely to see an increase in the frequency of these things. As we lose ice from Greenland we are taking the weight off, which may trigger earthquakes.’

Inland earthquakes in Britain are more common than people think. There are hundreds of magnitude one quakes each year. In 2002, 116 earthquakes were located in the Manchester area alone, with magnitudes ranging from 1.3 to 3.9.

Although it is unlikely Britain will be hit by a major earthquake, scientists are alarmed by one key factor in this year’s Haiti disaster: no one knew there was an earthquake problem. Port-au-Prince is next to a major plate boundary fault but because it hadn’t moved in hundreds of years details of the last major occurrence were only found in dusty history books.

One of the strongest earthquakes to hit Britain was on April 6, 1580. It had a magnitude of about 5.5 and its epicentre was in the Dover Straits. Although just two people died, the BGS warns it could happen again and this time the population is 40 times larger.

Tornadoes, on the other hand, are rife. With an average of 33 a year, Britain has the highest frequency per unit area in the world.

Alister Chapman is a professional storm chaser in Britain. He says: ‘The problem with tornadoes is they are almost impossible to study. We are learning a lot and we know what weather conditions are needed but not the trigger mechanism causing them.’

Flooding is an obvious risk – just ask residents in Cornwall who were hit last week, and those in Cumbria who are still clearing up last year’s devastation.

Climate change is one factor, although increasing urbanisation and the consequent building on flood plains is exasperating the problem. The Environment Agency estimates one in six homes in England is at risk of flooding.

According to the Met Office, winter rain will get worse over the next 30 years, and Britain’s frosty winters could disappear. Summer rain may decrease as Britain heats up but the downpours will be more intense. In the absence of earthquakes and tsunamis, at least that will give us something to whinge about.